There has been known a technique for suppressing the effect of hysteresis properties (application history properties of control voltage) and capacitance aging properties (such as change in capacitance over time, change in capacitance due to continuous application of control voltage, or failure of the capacitance to recover while the control voltage is not applied) of a variable capacitance capacitor including a ferroelectric material, as disclosed in Japanese Patent Application Publication No. 2012-209828. The invention of this publication employs a variable capacitance capacitor for adjusting the resonance frequency in a communication device performing noncontact communication. This technique includes applying a bias voltage alternately to the opposite terminals of a variable capacitance capacitor during a length (e.g., 2.2 seconds) of communication, instead of applying a bias voltage to only one of the opposite terminals during a length of communication. The length of applying a bias voltage is designed to be substantially equal for the opposite terminals. The above publication also discloses that one of the terminals receives a bias voltage during a length of communication, while the other terminal receives a bias voltage during the same length as a dummy voltage not used for communication.
However, the above publication does not include sufficient discussion on the hysteresis properties and the capacitance aging properties of a variable capacitance device including a ferroelectric material. In particular, it does not take account of the necessity of applying a bias voltage based on the length of communication. Further, it also does not take account of the asymmetry of response to application of a bias voltage depending on the configuration of the variable capacitance device.